MINOR: spoe: Check uniqness of SPOE engine names during config parsing

The engine name is now kept in "spoe_config" struture. Because a SPOE filter can
be declared without engine name, we use the SPOE agent name by default. Then,
its uniqness is checked against all others SPOE engines configured for the same
proxy.

  * TODO: Add documentation
diff --git a/doc/SPOE.txt b/doc/SPOE.txt
index 611b228..48cfa02 100644
--- a/doc/SPOE.txt
+++ b/doc/SPOE.txt
@@ -140,6 +140,9 @@
 found in the SPOE configuration file. All the file is considered to be in the
 same anonymous and implicit scope.
 
+The engine name must be uniq for a proxy. If no engine name is provided on the
+SPOE filter line, the SPOE agent name is unsed by default.
+
 2.2. "spoe-agent" section
 --------------------------
 
diff --git a/include/types/spoe.h b/include/types/spoe.h
index 193c2f6..2d94e36 100644
--- a/include/types/spoe.h
+++ b/include/types/spoe.h
@@ -237,6 +237,8 @@
 
 /* SPOE filter configuration */
 struct spoe_config {
+	char              *id;          /* The SPOE engine name. If undefined in HAProxy config,
+					 * it will be set with the SPOE agent name */
 	struct proxy      *proxy;       /* Proxy owning the filter */
 	struct spoe_agent *agent;       /* Agent used by this filter */
 	struct proxy       agent_fe;    /* Agent frontend */
diff --git a/src/flt_spoe.c b/src/flt_spoe.c
index dbc9d30..44e6724 100644
--- a/src/flt_spoe.c
+++ b/src/flt_spoe.c
@@ -2745,6 +2745,7 @@
 		struct spoe_agent *agent = conf->agent;
 
 		spoe_release_agent(agent);
+		free(conf->id);
 		free(conf);
 	}
 	fconf->conf = NULL;
@@ -2755,9 +2756,30 @@
 static int
 spoe_check(struct proxy *px, struct flt_conf *fconf)
 {
+	struct flt_conf    *f;
 	struct spoe_config *conf = fconf->conf;
 	struct proxy       *target;
 
+	/* Check all SPOE filters for proxy <px> to be sure all SPOE agent names
+	 * are uniq */
+	list_for_each_entry(f, &px->filter_configs, list) {
+		struct spoe_config *c = f->conf;
+
+		/* This is not an SPOE filter */
+		if (f->id != spoe_filter_id)
+			continue;
+		/* This is the current SPOE filter */
+		if (f == fconf)
+			continue;
+
+		/* Check engine Id. It should be uniq */
+		if (!strcmp(conf->id, c->id)) {
+			Alert("Proxy %s : duplicated name for SPOE engine '%s'.\n",
+			      px->id, conf->id);
+			return 1;
+		}
+	}
+
 	target = proxy_be_by_name(conf->agent->b.name);
 	if (target == NULL) {
 		Alert("Proxy %s : unknown backend '%s' used by SPOE agent '%s'"
@@ -3707,6 +3729,7 @@
 	}
 
  finish:
+	conf->id    = strdup(engine ? engine : curagent->id);
 	conf->agent = curagent;
 	list_for_each_entry_safe(mp, mpback, &curmps, list) {
 		LIST_DEL(&mp->list);